Bonding patterns and instabilities in the m=2 Ruddlesden-Popper phases:: LaSr2Mn2O7 and La2CaCu2O6
Bonding patterns and instabilities in the m=2 Ruddlesden-Popper phases:: LaSr2Mn2O7 and La2CaCu2O6
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DOI：
10.1039/a706965k
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发表时间：
1998-03-01
影响因子：
--
通讯作者：
Tremel, W
中科院分区：
文献类型：
--
作者：
Felser, C;Seshadri, R;Tremel, W
我们展示了重要层状化合物 LaSr2Mn2O7 和 La2CaCu2O6 的高水平能带结构计算结果；两者都具有 Ruddlesden-Popper 相 m = 2 成员的结构，并且由双钙钛矿板与岩盐板的共生组成。铜酸盐还具有有序的氧缺陷。为了进一步比较，还计算了四方La2CuO4的能带结构。亚锰酸盐是一种表现出巨磁阻（GMR）效应的材料，并且可以掺杂铜酸盐以形成超导体。计算是使用 TB-LMTO-ASA 程序在局部（自旋）密度近似 L(S)DA 内进行的；对于锰酸盐，自旋极化计算导致磁性基态；比较了铁磁体和两种反铁磁结构的计算。计算显示了这两种结构相关的化合物的键合模式之间的相似性和差异，它们在掺杂时表现出截然不同的基态。然而，费米表面上或附近的不稳定性可能与不同基态的稳定有关，但其性质非常相似。
We present the results of high level band structure calculations on the important layered compounds LaSr2Mn2O7 and La2CaCu2O6; both of which have the structure of the m = 2 member of the Ruddlesden-Popper phases and comprise intergrowths of double perovskite slabs with rock-salt slabs. The cuprate additionally has an ordered oxygen defect. For further comparison, the band structure of tetragonal La2CuO4 has also been calculated. The manganite is a material exhibiting giant magnetoresistance (GMR) effects and the cuprates can be doped to give superconductors. The calculations have been performed using the TB-LMTO-ASA programs within the local (spin) density approximation L(S)DA; for the manganite, spin-polarized calculations result in a magnetic ground state; calculations on the ferromagnet and two antiferromagnetic structures are compared. The calculations show up similarities and differences between the bonding patterns of these two structurally related compounds that display widely different ground states when they are doped. The instabilities on or near the Fermi surface possibly implicated in the stabilization of the different ground states are, however, quite similar in character.